Pump

ABSTRACT

A liquid pump has a rotor in a pump housing which has a pump chamber, a pump base, a pump-chamber wall and a cover. The rotor rotates just above the pump base, the pump-chamber wall being provided around the outside of and slightly spaced apart from the rotor and having a heating means thereon. An inlet to the rotor is provided centrally in the axial direction towards the rotor and an outlet from the pump housing is provided externally at the periphery of the pump-chamber wall. Blade-like guiding elements which are integrally injection-moulded thereon are arranged on the pump base, radially outside the impeller.

This application is a National Stage application, filed under 35 U.S.C. §371, of International Application PCT/EP2011/069810, filed Nov. 10, 2011, which claims priority to German Application No. 10 2010 043 727.1, filed Nov. 10, 2010, both of which are hereby incorporated by reference in their entirety.

TECHNOLOGICAL FIELD

The invention relates to a pump, in particular to a liquid pump, which comprises a rotor or an impeller in a pump housing.

BACKGROUND

From U.S. Pat. No. 6,736,598 B2 a liquid pump is known, which comprises a pump housing having a rotor or impeller arranged therein. A heating element is provided at the exterior wall of the pump chamber or of the pump housing.

WO 2010/034488 A1 describes another liquid pump including a rotor or impeller in a pump housing. In this case, a heating element can be provided in a pump chamber of the pump housing, or as an alternative also externally on a pump chamber wall. The rotor comprises a central inlet directed towards said rotor in axial direction. An outlet from the pump housing is provided on the outer periphery of the pump chamber wall in radial direction.

BRIEF SUMMARY

The object underlying the present invention is to provide an aforementioned pump by means of which problems of the prior art can be prevented and in particular by means of which a very efficiently-working pump can be provided that can be produced by simple ways and means.

The object is achieved by a pump. Advantageous as well as preferred embodiments of the invention are subject-matter of the dependent claims and will be explained in more detail in the following. The wording of the claims is incorporated into the content of the description by explicit reference.

It is provided that the pump housing comprises a pump chamber including a pump bottom, a pump chamber wall as well as a cover thereon. The rotor rotates above the pump bottom, advantageously at a small distance thereto. The pump chamber wall extends around the rotor, advantageously at a certain distance thereto, and comprises a heating means. An inlet towards the rotor or the pump chamber is provided centrally and in axial direction towards the rotor. An outlet from the pump housing or the pump chamber is provided on the outer periphery of the pump housing or of the pump chamber wall.

According to the invention, guide elements are provided at the pump bottom which are arranged radially outside of the rotor, i.e. surrounding the latter. The advantage of said guide elements is that they guide the liquid current inside the pump in an especially well manner, in particular towards a pump chamber wall heated by means of the heating means. Thus, an optimized input of heat from the heating means into the pumped liquid is effected. The guide elements can cause that the number of rotations or circulations of the water along the pump chamber wall and thus along the heating means is increased or that an additional rotation of the water inside the pump along the heated pump chamber wall takes place, respectively. Due to the fact that the pump chamber wall is flown against flatly and, so to say, with minimized transition, a current rupture can be prevented, wherein the angle is supposed to be very flat or acute by means of the configuration of the guide elements. In this case, the liquid current advantageously flows along the pump chamber wall towards the outlet.

Advantageously, the guide elements are not only provided at the pump bottom, but even arranged thereon or fixed thereto. Advantageously, the pump bottom can be configured integrally and in one piece with the guide elements thereon. In this case, production in one piece from plastics lends itself. This way, indeed the production of the pump bottom is slightly more elaborate, however, an additional assembly step for the guide elements can be dispensed with. Furthermore, the position of the guide elements in relation to the rotor, which can also be supported at the pump bottom or at least be supported with reference thereto, can be improved or configured more exactly. This can increase the efficiency of the pump. Another advantage of such guide elements, besides the increased efficiency or heating effect of the pump, is that the noise generation inside the pump is reduced because of a current guided in a better manner.

In a further embodiment of the invention, the guide elements can be configured in a curved manner in radial direction. In this case, they can be bent or curved in the rotation direction of the rotor. Thus, they can advantageously have the form of so-called guide blades for a particularly favorable guiding of the liquid current.

In an embodiment of the invention, it is of advantage if the guide elements reach almost as far as up to the pump chamber wall. Thus, the internal face of the pump chamber wall is flown against as precisely as possible. A distance of a few millimeters up to one or two centimeters can be sufficient. Towards the inside, the guide elements can approach the rotor or impeller relatively closely. Here, a distance can be a few millimeters.

Advantageously, the rotor can be slightly more embedded into the pump bottom than lower or radially inner regions of the guide elements. This can in particular apply to a rotor bottom part so that rotor blades extending on the rotor bottom part are quasi continuously continued in their course by the guide elements. This continuation of the course applies to both the curvature along the rotation direction of the rotor and any other curvature. Said curvature can also be present such that both the rotor blades and the guide elements extend away from the pump bottom in a bent or curved course as from a certain point. Up to said point, the rotor blades can be curved as from a rotor central region downwards towards the pump bottom.

In an embodiment of the invention, it can be provided that the pump chamber including the cover on top or its sealing extends upwards almost up to the rotor, namely into the direction towards the pump bottom. In this case, the cover of the pump is the region which limits the pump chamber around the inlet upwards or which is located inside the pump chamber wall, respectively. In this case, it can even be provided that the cover partially is below the topmost region of the rotor, preferably in the rotor central region thereof, so that the cover slightly follows the course of the rotor with its shape. Towards the outside, the cover bends away from the rotor and rises far above said rotor or the pump bottom in the direction towards the pump chamber wall. Said bending of the cover away from the rotor can advantageously be effected approximately at the external diameter of the rotor. Thus, above the guide elements, the cover ascends strongly again and releases a certain space above said guide elements, which space can be used by the liquid current to stream along the pump chamber wall.

Approximately three to twenty of such guide elements can be provided at the pump. Advantageously, there are six to eight guide elements. It is possible to provide as many rotor blades as guide elements. However, this is not mandatory, in particular also more guide elements than rotor blades can be provided.

In a further embodiment of the invention, the outlet of the pump chamber can be arranged on the radial outer periphery of the pump chamber. Said outlet can be formed by means of a course of the pump chamber that ascends more and more upwards away from the pump bottom. Here, in the upper region, the pump chamber has a ring-shape, since radially inwards, the cover of the pump chamber extends obliquely upwards. The outlet can lead out of the pump chamber in rotation direction or circumferential direction, quasi as tangential output of the liquid.

Advantageously, the pump chamber wall is configured integrally or in one piece with the heat element thereon. If, here, a shock or the like can be prevented into the circumferential direction, the liquid can stream along a smooth surface and there will not be so many swirls. Indeed, compared to a swirled liquid current, the heat transfer slightly deteriorates. However, this can easily be counterbalanced in that especially also the guide elements can cause an additional circulation of the liquid current along the heated pump chamber wall so that a corresponding heat transfer or heating of the liquid can take place.

These features and further features arise, besides from the claims, also from the description and the drawings, wherein the individual features can be realized in each case on their own or in the form of sub-combination of multiple features in an embodiment of the invention and on other fields and can represent advantageous embodiments as well as embodiments capable of being protected, for which protection is claimed in this case. The division of the application into individual sections and cross headings does not limit the general validity of the statements made therein.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

One exemplary embodiment of the invention is schematically shown in the drawings and will be explained in more detail in the following. The drawings show in:

FIG. 1 a section through a pump according to the invention,

FIG. 2 an oblique plane view of a partially disassembled pump or a view into the housing thereof, and

FIG. 3 a plane view of the illustration according to FIG. 2.

DETAILED DESCRIPTION

In FIG. 1, a pump 11 is shown, which can be used particularly well for a dishwasher or a washing machine. The pump 11 comprises a pump housing 12, the course of which can be seen from the checked and hatched illustration. In this case, it can be seen that a motor 14 for driving the pump 11 is arranged in or on a housing bottom 13.

A cover 15 of the pump housing 12 is configured with a depression 15′ extending from outside to downwards inside, which depression circumferentially has an approximately constant distance to the housing bottom 13. Inside the depression 15′, there is an inlet tube 16 which is formed integrally to the cover 15. Said tube is arranged exactly centrally above the dot-dashed central longitudinal axis of the pump 11, along which also a rotational axis of the motor 14 is running.

The housing bottom 13 and the cover 15 are interconnected by means of a side wall 17 or said three parts essentially form the pump housing 12. As can be seen, without further explanation, the side wall 17 rests against the housing bottom 13 and the cover 15 in a sealed manner by means of multiple sealings 18.

In this case, the side wall 17 is configured as heating element. For this purpose, it advantageously consists of a support material such as metal, in particular stainless steel, where appropriate alternatively of temperature-resistant plastic. Onto said support material, a heating element is applied in a planar manner which can be effected, if applicable, as usual and with an insulation layer underneath. Advantageously, this is effected at the exterior side facilitating an electrical connection and reducing insulation problems. The heating elements can advantageously be applied using thick film technology, which is generally known to the person skilled in the art and which will therefore not be explained in more detail here.

Just marginally above the housing bottom 13, an impeller 20 is supported as rotor on a shaft of the motor 14, the shape of which impeller is also known per se. Said impeller comprises impeller blades 21 which cannot be seen very well in the sectional view of FIG. 1, which is why reference is made to the oblique view of FIG. 2.

Regarding the configuration of the cover, it is to be noted that the upper edge thereof gradually extends upwards in the circumferential direction as far as up to the elevation 15″. Said elevation then merges into an outlet tube 19 as generally known per se from such impeller pumps.

The three parts of the pump housing 12 are held together via two external connectors 22. According to the illustrations in FIGS. 2 and 3, four such connectors 22 are provided.

On the upper side of the housing bottom 13, which is composed of plastic, multiple guide elements 24 are provided. As can be seen from the right guide element 24 in sectional view of FIG. 1, the seven guide elements 24 are integrally formed to the housing bottom 13, in particular injection-molded. This is not a problem in case of a production of plastics. The elongate and curved or bent shape of the guide elements 24 can also well be seen from the FIGS. 2 and 3. Towards the inside, they extend almost up to the impeller 20, and towards the outside they have a slight distance to the side wall 17, for example several millimeters. In this case, it is obvious that seven guide elements 24 are provided and five impeller blades 21. The latter are shown in the plane view with dashed lines. Furthermore, FIG. 3 shows that the curvature of the impeller blades 21 is inverse to the curvature of the guide elements 24. However, this is also generally known to the person skilled in the art.

Furthermore, as can be seen from FIGS. 1 and 2, the guide elements 24 are configured such that in the region towards the impeller 20, they have approximately the height of said blades or slightly surpass the height of the impeller blades 21. The height of the guide blades can vary in the course of the blades, it can, for example, decrease towards the outside and even become zero, if appropriate.

It can also be seen from FIG. 1 that the housing bottom 13 in the region the guide elements 24 rest on it or are integrally shaped thereto, extends upwards towards the outside, that is extending upwards outside of the impeller 20. As a result, also a transport of the water supplied by the pump 11 upwards is facilitated or effected. The water supplied effects multiple circulations inside the pump housing 12 before it is transported that high that it leaves the pump 11 again through the elevation 15′ and the outlet tube 19. A kind of deflection plate helps to transport the water upwards. However, said plate does not contribute to the number of circulations of the water. It can also be seen from FIG. 1, that the interior of the pump housing actually essentially forms a circular ring-type volume. In particular, it is to be observed in case of said shape of the pump housing 12 or the internal space respectively, that the ratio between volume and area of the side wall 17 is relatively small, i.e. that the side wall 17 is relatively large compared to the volume. This can quasi be seen from the distance between the side wall 17 and the cover 15 above the depression 15′ of the cover. In case the entire pump housing 12 is filled with the water to be transported, a water volume streaming along the side wall 17 can very well be heated by means of the heating element function of said wall. The fact that the water transported indeed is subject to several circulations inside the pump housing 12, as explained above, even improves said effect.

For transporting or directing the water, the aforementioned guide elements 24 are of major importance. Said elements additionally put the water into circulation and direct it towards the side wall 17 in the aforementioned flat angle. Thus, the result is a very good and rapid nestled current. This can hardly be achieved that well only by means of the impeller 20 alone or the impeller blades 21 thereof.

The additional advantage according to the invention of the preferred integral molding of the guide elements 24 to the housing bottom 13 is the simpler producibility, since in this case the housing bottom 13 can be produced as injection molded part entirely. As a result, the guide elements 24 are also fixed to the housing bottom 13 in a significantly more stable manner. Furthermore, they can be provided with smooth transitions and without gaps or the like at the housing bottom 13, so that here the liquid current can be guided as good as possible and to the desired extent. As a result of the impeller 20 being embedded slightly more into the housing bottom 12 according to FIG. 1, it can be achieved that radially outside thereof, the housing bottom 13 is guided outwards exactly in the lower regions of the impeller blades 21. This way, the liquid current can likewise be guided most advantageously.

The side wall 17 can, as can be seen from FIGS. 2 and 3, be configured as closed circular ring, that is to say without a joint or the like. Said wall can either be composed of a seamless tube or been cut off from a longer tube of such type. As an alternative, it can be bent from a metal sheet strip, the end edges of which are connected as butt joint, however smooth or in a manner, that the abutting is closed and smoothened afterwards. The subsequent application of the heating device thereon is not a problem, since mainly also thick film heating elements can be applied on curved faces by means of corresponding printing methods. 

1. A pump, in particular a liquid pump, including a rotor or an impeller in a pump housing which comprises a pump chamber, a pump bottom, a pump chamber wall as well as a cover, wherein said rotor rotates above said pump bottom at a small distance thereto, wherein around said rotor said pump chamber wall is provided with a heating means thereon, wherein an inlet to said rotor is provided centrally and in axial direction towards said rotor and an outlet from said pump housing is provided on an outer periphery of said pump chamber wall, wherein guide elements are provided at said pump bottom, which are arranged radially outside said rotor.
 2. The pump according to claim 1, wherein said pump bottom is configured integrally and in one piece with said guide elements thereon.
 3. The pump according to claim 1, wherein said bottom is of plastic.
 4. The pump according to claim 1, wherein said guide elements are configured such that a liquid current after exiting said rotor encounters said pump chamber wall at an acute angle.
 5. The pump according to claim 1, wherein said guide elements are configured such that said liquid current after encountering said pump chamber wall streams further along said pump chamber wall up to said outlet.
 6. The pump according to claim 1, wherein said guide elements extend in a curved manner in radial direction.
 7. The pump according to claim 1, wherein said guide elements are guide blades.
 8. The pump according to claim 1, wherein said guide elements are bent or bent-off into said rotation direction of said rotor.
 9. The pump according to claim 1, wherein said guide elements extend almost as far as up to said pump chamber wall.
 10. The pump according to claim 1, wherein said rotor is slightly more embedded into said pump bottom than lower parts of said guide elements.
 11. The pump according to claim 10, wherein said rotor has rotor blades, and said rotor blades in the course thereof have a steady continuation in said guide elements.
 12. The pump according to claim 10, wherein said continuation in said guide elements is also with a curvature or a curved form away from said pump bottom.
 13. The pump according to claim 1, wherein said pump chamber with said cover on top extends almost up to said rotor or to an upper side of said rotor facing said inlet.
 14. The pump according to claim 13, wherein said cover is configured as upper boundary of said pump chamber around said inlet radially outside said rotor extending away again from said rotor outwards, wherein said region is above said guide elements.
 15. The pump according to claim 1, wherein 3 to 20 of said guide elements are provided.
 16. The pump according to claim 15, wherein as much of said guide elements as said blades on said rotor or impeller, respectively, are provided.
 17. The pump according to claim 1, wherein said outlet from said pump chamber is arranged radially outside on said pump chamber and is configured as a course ascending more and more upwards away from said pump bottom of said pump chamber having a ring shape in said upper region.
 18. The pump according to claim 17, wherein said outlet leads out of said pump chamber in radial direction.
 19. The pump according to claim 1, wherein said pump chamber wall is configured integrally or in one piece with said heating element thereon and without a joint or the like into said circumferential direction. 